nickname for cement.
lâm-á is a brand name of a cement company (南亞)
khóng is probably the noun for "khōng" (?! Is it?) -- wrong, please see comment below.
khōng is the action of applying cement onto a mode of some sort.
Another term often heard is "khōng-kû-lí" from "a-ta-ma khōng kû-lí" (originated from Japanese?)
a-ta-ma = あたま means head in Japanese.
"a-ta-ma khōng kû-lí" literally: the brand is full of concrete, meaning stupid, jelly head.
khōng = 鞏 -- wrong, please see comment below.
Heard lâm-á khóng on radio. Lots of guesses in today's post. I'm not certain about any of this information. Correct ideas are welcome.